What is the recommended management of shingles (herpes zoster) in an adult, including antiviral therapy, pain control, and vaccination?

Management of Shingles (Herpes Zoster) in Adults

For acute shingles, initiate oral valacyclovir 1000 mg three times daily or famciclovir 500 mg every 8 hours within 72 hours of rash onset, combine with stepped analgesia starting with acetaminophen and adding gabapentin 100-300 mg at bedtime (titrating to 300-600 mg three times daily) from the acute phase to prevent postherpetic neuralgia, and ensure all adults ≥50 years receive the two-dose Shingrix vaccine series (2-6 months apart) for prevention. 1, 2

Acute Antiviral Therapy

First-Line Oral Regimens

• Valacyclovir 1000 mg three times daily for 7 days is the preferred oral antiviral due to superior bioavailability and more convenient dosing compared to acyclovir. 1, 2

• Famciclovir 500 mg every 8 hours for 7 days is an equally effective alternative offering comparable outcomes when initiated promptly. 1, 2

• Timing is critical: Start antivirals within 72 hours of rash onset to reduce lesion duration, acute pain intensity, and risk of postherpetic neuralgia. 1, 2

• Dose adjustment required: For patients with creatinine clearance <50 mL/min, reduce antiviral doses to avoid toxicity—this is especially important in older adults who frequently have reduced renal function. 2

Intravenous Therapy for Severe Disease

• Acyclovir 10 mg/kg IV every 8 hours for 21 days is indicated for herpes zoster with CNS complications (meningoencephalitis, myelitis), disseminated disease, or in immunocompromised patients with severe presentations. 1, 2

Pain Management: Stepped Analgesic Approach

Mild to Moderate Pain (First-Line)

• Acetaminophen 3000-4000 mg/day in divided doses is the preferred initial analgesic due to its lower adverse-effect profile in older adults. 1, 2

• NSAIDs should be used with extreme caution in older adults due to risks of gastrointestinal toxicity, renal impairment, hypertension, and heart failure; routine monitoring of GI symptoms, renal function, blood pressure, and drug interactions is mandatory. 1

Moderate to Severe Pain (Second-Line)

• Opioids should be initiated at low doses with gradual titration, using scheduled dosing for continuous or frequent pain rather than as-needed administration. 1, 2

• Anticipate and manage opioid adverse effects: sedation, anticholinergic properties, cognitive impairment, falls, and constipation are common and require proactive management. 1, 2

Neuropathic Pain Prevention: Early Adjuvant Therapy

Gabapentin (Preferred for PHN Prevention)

• Start gabapentin during the acute phase at 100-300 mg at bedtime, gradually titrating to 300-600 mg three times daily as tolerated to reduce the risk of postherpetic neuralgia. 1, 2

• This early initiation alongside conventional analgesics is recommended by the American Geriatrics Society specifically to prevent the transition from acute to chronic neuropathic pain. 1, 2

Tricyclic Antidepressants (Alternative)

• Nortriptyline 10-25 mg at bedtime is preferred over amitriptyline in older adults due to its lower anticholinergic burden; start at low doses and titrate slowly. 1, 2

Topical Therapies for Localized Pain

• Lidocaine 5% patches (up to 3 patches for 12 hours daily) provide safe, non-systemic pain relief with no documented systemic absorption or toxicity—particularly valuable for elderly patients with renal impairment or polypharmacy. 1, 2

• The 5% prescription strength is significantly more effective than 4% over-the-counter formulations or lidocaine gel/cream. 1

• Capsaicin topical therapy may benefit a small proportion of patients but is often poorly tolerated. 1, 2

Medications to Avoid in Older Adults

• Never use muscle relaxants (cyclobenzaprine, carisoprodol) due to significant anticholinergic effects and increased fall risk. 1, 2

• Avoid benzodiazepines due to sedation, cognitive impairment, and increased fall risk. 1, 2

• Systemic corticosteroids are not routinely recommended for herpes zoster in older adults due to heightened risks of hyperglycemia, hypertension, glaucoma, and peptic ulcer disease. 2

Vaccination for Prevention: Shingrix (Recombinant Zoster Vaccine)

Standard Recommendations

• All adults ≥50 years should receive the two-dose Shingrix series with the second dose given 2-6 months after the first (minimum interval 4 weeks). 3, 1, 4

• Efficacy is exceptional: 97.2% in adults ≥50 years, 91% in those ≥70 years, and 89% against postherpetic neuralgia, with protection persisting >83% for at least 8 years. 1, 4, 2

Immunocompromised Adults

• Shingrix is recommended for immunocompromised adults ≥18 years (hematologic malignancies, transplant recipients, HIV, autoimmune diseases on immunosuppressants, JAK inhibitors, biologics) with a shortened schedule of 1-2 months between doses. 3, 4

• Never use live-attenuated Zostavax in immunocompromised patients—only Shingrix is appropriate due to the risk of disseminated VZV infection with live vaccines. 3, 4

Vaccination After Prior Shingles Episode

• Vaccinate even after a prior shingles episode once acute symptoms have resolved, ideally waiting at least 2 months after the episode. 4

• The 10-year cumulative recurrence risk is 10.3%, making vaccination essential despite prior infection. 4

Revaccination After Prior Zostavax

• Adults who previously received Zostavax should receive the full 2-dose Shingrix series at least 2 months after the last Zostavax dose, as Zostavax efficacy declines to only 14.1% by year 10. 4

Special Considerations in Older Adults

• Older adults have increased risk of drug accumulation due to increased fat-to-lean body mass ratio, slowed GI transit, and reduced renal clearance—requiring careful dose selection and monitoring. 1

• Pharmacokinetic changes necessitate lower starting doses and slower titration of all medications, particularly opioids, gabapentin, and tricyclic antidepressants. 1

Common Pitfalls to Avoid

• Do not delay antiviral therapy beyond 72 hours of rash onset—efficacy diminishes significantly after this window. 1, 2

• Do not withhold vaccination due to age—there is no upper age limit for Shingrix, and older adults benefit most from prevention. 4

• Do not restart the Shingrix series if the second dose is delayed beyond 6 months; simply administer the second dose as soon as possible. 4

• Do not order VZV antibody titers before vaccinating adults ≥50 years—guidelines explicitly recommend against serologic screening, as 88-91% of adults are seropositive regardless of recalled chickenpox history. 4